The last time a Phillies starter was headed for the shelf, Adam Morgan made for an impractical fill-in. By the time John Lannan was officially DL’d the morning of Apr. 18, the prized 23-year-old lefty was already five innings deep into his scheduled start for the IronPigs that afternoon. So if Morgan was going to be the one to get the ball for Lannan’s next turn, he’d have had to do it on short rest.

The organization opted against it.

With Roy Halladay likely headed to the DL with what he and GM Ruben Amaro described yesterday as “discomfort” in his throwing shoulder, and with Morgan’s throwing schedule making for a seamless switch, there are grounds for a different kind of uneasiness.

Morgan didn’t look too good yesterday either and hasn’t in a while.

Morgan was lit up for four runs in four innings on Sunday against Indianapolis – incidentally, the Triple-A affiliate of the team that blasted Halladay for eight runs in 3 2/3 in his second-to-last time out, the Cleveland Indians. The 140-character scouting report:

Adam Morgan up to 86 P with 2 outs in the 4th. Not looking sharp at all

After surrendering no more than two runs in any of his first three starts (1.42 ERA), Morgan’s been served four runs in each of the three since (6.89 ERA).

On paper, the alternatives aren’t exactly enticing either. Ethan Martin, ranked 76th on MLB.com’s pre-2013 top 100 prospect list (Morgan was No. 92 on Keith Law’s list), has surrendered 14 earned in 13 innings over his three most recent times out. Martin’s next scheduled turn is tomorrow, so the organization could give him a reduced load then to make him available for May 10 in Arizona.

Obviously, minor league performance – both good and bad – doesn’t always translate.

Tyler Cloyd was crushed for a 4.91 ERA in six starts with the Phillies last year after going 12-1 with a 2.35 ERA at Triple-A and grabbing International League MVP honors. And though he was mushed for 10 earned in 9 1/3 innings through two starts at Lehigh Valley this year, Jonathan Pettibone has been pretty serviceable for the varsity team, going 2-0 with a 3.24 ERA in three starts, all Phillies wins.

Morgan’s probably the ideal option, not only because of the timing and his pedigree, but also because of how he manned up on Mar. 22 – the last time Halladay had to be plucked from the rotation, in spring training. With little notice, Morgan dealt the Braves 4 2/3 innings of one-run ball.

But as bad as Halladay’s been, due to injury or whatever else, you’d have to think anyone the Phillies throw on Friday will at this point be an upgrade – if only because he’ll likely be able to last in games and preserve the bullpen so the team can be competitive for the rest of the series.

Just know: if you’re sifting through minor league box scores for hope, you’re not likely to find it.